If you care about unlocking your iPhone 3g do not update to 2.2.1 unless you are updating custom firmware with the baseband update removed. QuickPwn can not create this custom firmware. Currently PwnageTool 2.2.5 (on OS X) is the only way to make this custom 2.2.1 .ispw with the baseband update removed. Upgrading to 2.2.1 via iTunes and then jailbreaking via QuickPwn will result in no unlock for you!

iPhone 2g owners you are safe to upgrade to 2.2.1, jailbreak with QuickPwn and unlock no problems.

iPod Touch 1g owners. You haven't had baseband worries for ages. Have fun